CODEWITHSUNDEEP
c#memory-leaks
Ryan Foster
Ryan Foster

Reputation: 51

Could there be a potential memory leak using Directory.GetDirectories()?

foreach (string path in mainFolders)
    {
        if (!Directory.Exists(path))
            continue;

        Stack<string> pathsToCheck = new Stack<string>(Directory.GetDirectories(path));

        while (pathsToCheck.Count > 0)
        {
            try
            {
                string cPath = pathsToCheck.Pop();
                string[] dir = Directory.GetDirectories(cPath);

                if (dir.Length > 0)
                    foreach (string s in dir)
                        pathsToCheck.Push(s);
                else
                    folderPaths.Add(cPath.Replace('\\', '/'));
            }
            catch (Exception e)
            {
                errors.Add(e.Message);
            }
        }
    }

So basically what I'm trying to do is take a list of folder paths and get all of the subdirectories from them. Sometimes this seems to be causing memory usage upwards of 9GB (as said by Task Manager), and while there can be a ton of folders it's checking (most I've checked was 45,000 folders) that's still a relatively small amount of memory.

So is there something wrong I'm not catching that could be leaking that much memory? I'm doing it this way because just Directory.GetDirectories() fails as soon as it comes across a folder that it can't read. I'm using Unity and am stuck with .NET 2.0.

Upvotes: 0

Views: 439

Answers (1)

Christopher
Christopher

Reputation: 9824

A pet peeve of mine is faulty exception handling. And yours can swallow Fatal Exceptions, wich is a deadly sin of exception handling. He are two articles I link often:

http://blogs.msdn.com/b/ericlippert/archive/2008/09/10/vexing-exceptions.aspx http://www.codeproject.com/Articles/9538/Exception-Handling-Best-Practices-in-NET

First, you can not do memory measurement with the Task Manager. The values are less the useless: http://www.itwriting.com/dotnetmem.php

Secondly before you try to debug a presumed memory leak, you need to understand how the GC works. In particular that it will try to avoid running until application closure if at all possible: https://social.msdn.microsoft.com/Forums/en-US/286d8c7f-87ca-46b9-9608-2b559d7dc79f/garbage-collection-pros-and-limits?forum=csharpgeneral

There are only a few possible Memory Leak scenarios in .NET:

  • you add something to a collection, but forget to take it out again later. This memory leak only happens at runtime, as the application closure will still clean everything up
  • You are handling unmanaged resoruces and the writer of the class screwed up the Dispose/Fianlize pattern. Dispose is mandatory. Finalize is a optional thing for use convenience.

Upvotes: 1

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